This invention relates to a combustion chamber for an internal combustion engine and more particularly to a direct cylinder injected engine.
In the search to obtain better engine performance while at the same time maintaining good fuel economy and exhaust emission control, direct cylinder injection has been proposed. However, there are several problems in connection with the use of direct cylinder injection, particularly with high-performance engines.
Obviously if the engine employs direct cylinder injection, it is then necessary to mount the fuel injector in the cylinder head along with the other components therein. Thus, if multi-valve engines are employed, there remains little area available for the fuel injector. The problem is further compounded by the manifolding and cylinder head flow passages required to obtain optimum performance.
It is, therefore, a principal object of this invention to provide an improved combustion chamber and induction system for a direct cylinder fuel-injected engine.
It is a further object of this invention to provide a cylinder head arrangement for an engine that permits the use of multiple valves and direct cylinder fuel injection while maintaining the desired flow path from the fuel injector.
In conjunction with direct cylinder injected engines, it is also generally the practice to try to position the spark plug in or near to the geometric center of the combustion chamber. In order to position the fuel injector in a location wherein it can be easily serviced and will not interfere with the other components of the combustion chamber, it has been proposed to place the injector at a side of the chamber between the intake valves and so that it sprays generally toward the cylinder bore axis.
When the fuel injector is mounted at the side of the combustion chamber and particularly in the side of the cylinder head, there are certain problems which arise. The first of these problems has to do with the adequate cooling of the fuel injector. A centrally positioned fuel injector can easily have a water jacket which surrounds it and is in close proximity to it. However, in the area adjacent the cylinder block and where the cylinder head and cylinder block meet, it is normally the practice to provide flow passages which communicate the cylinder head and cylinder block cooling jackets with each other. These normally do not leave adequate space for cooling of the fuel injector.
It is, therefore, a principal object of this invention to provide an improved cylinder head arrangement for a direct injected engine having a side position fuel injector and wherein the injector is adequately cooled.
It is a further object of this invention to provide an improved cooling arrangement for the fuel injector of a direct injected engine.
In conditions where it is desirable to maintain a homogeneous fuel/air mixture, it has been found that the fuel can be mixed better with the air when the spray path of the injector is parallel to and closely adjacent the induction system axis. In this way, the fuel and air will be flowing in the same general direction and mixing and homogeneous charge can be ensured.
It is, therefore, a still further object of this invention to provide an improved cylinder head and fuel injector mounting arrangement for an engine wherein the injector is positioned parallel to the intake flow path.
Also in connection with the induction and injection system, there are many times when it is desirable to provide a control valve in the induction system. This control valve can be utilized to redirect the flow of the charge into the combustion chamber and/or accelerate it to attain certain types of motion during certain engine running conditions. Again, when this is done it is important that the injector and the control valve be appropriately positioned relative to each other to achieve the desired flow effect and still ensure that the fuel will be mixed with the air to the desired degree.
It is, therefore, a still further object of this invention to provide an improved cylinder head arrangement for a direct injected engine having an intake control valve and wherein the injector control valve and intake path are optimally positioned.
As has been noted, there are required flow passages that extend through the interface between the cylinder head and the cylinder block for cool and flow between the respective cooling jackets. These flow paths generally extend around the cylinder bores and thus provide some weakening in both the cylinder head and cylinder block.
When the fuel injector is also mounted in the cylinder head and at a side of the cylinder bore, an opening must be formed in the cylinder head surface through which the injector can inject fuel. This opening can further weaken the cylinder head.
It is, therefore, a still further object of this invention to provide an improved cylinder head construction for a direct injected engine wherein the injector opening in the cylinder head is spaced from the hold-down fasteners between the cylinder head and cylinder block to avoid weakening in the clamping area.